Job.Scale should not result in job update or eval create if args.Count == nil

plus tests

api/jobs_test.go

@@ -1595,18 +1595,20 @@ func TestJobs_ScaleAction(t *testing.T) {
 	require.Contains(err.Error(), "not found")
 
 	// Register the job
-	_, wm, err := jobs.Register(job, nil)
+	regResp, wm, err := jobs.Register(job, nil)
 	require.NoError(err)
 	assertWriteMeta(t, wm)
 
 	// Perform scaling action
 	newCount := groupCount + 1
-	resp1, wm, err := jobs.Scale(id, groupName,
+	scalingResp, wm, err := jobs.Scale(id, groupName,
 		intToPtr(newCount), stringToPtr("need more instances"), nil, nil, nil)
 
 	require.NoError(err)
-	require.NotNil(resp1)
-	require.NotEmpty(resp1.EvalID)
+	require.NotNil(scalingResp)
+	require.NotEmpty(scalingResp.EvalID)
+	require.NotEmpty(scalingResp.EvalCreateIndex)
+	require.Greater(scalingResp.JobModifyIndex, regResp.JobModifyIndex)
 	assertWriteMeta(t, wm)
 
 	// Query the job again
@@ -1614,7 +1616,47 @@ func TestJobs_ScaleAction(t *testing.T) {
 	require.NoError(err)
 	require.Equal(*resp.TaskGroups[0].Count, newCount)
 
-	// TODO: check if reason is stored
+	// TODO: check that scaling event was persisted
+}
+
+func TestJobs_ScaleAction_Noop(t *testing.T) {
+	t.Parallel()
+	require := require.New(t)
+
+	c, s := makeClient(t, nil, nil)
+	defer s.Stop()
+	jobs := c.Jobs()
+
+	id := "job-id/with\\troublesome:characters\n?&字\000"
+	job := testJobWithScalingPolicy()
+	job.ID = &id
+	groupName := *job.TaskGroups[0].Name
+	prevCount := *job.TaskGroups[0].Count
+
+	// Register the job
+	regResp, wm, err := jobs.Register(job, nil)
+	require.NoError(err)
+	assertWriteMeta(t, wm)
+
+	// Perform scaling action
+	scaleResp, wm, err := jobs.Scale(id, groupName,
+		nil, stringToPtr("no count, just informative"), nil, nil, nil)
+
+	require.NoError(err)
+	require.NotNil(scaleResp)
+	require.Empty(scaleResp.EvalID)
+	require.Empty(scaleResp.EvalCreateIndex)
+	assertWriteMeta(t, wm)
+
+	// Query the job again
+	resp, _, err := jobs.Info(*job.ID, nil)
+	require.NoError(err)
+	require.Equal(*resp.TaskGroups[0].Count, prevCount)
+	require.Equal(regResp.JobModifyIndex, scaleResp.JobModifyIndex)
+	require.Empty(scaleResp.EvalCreateIndex)
+	require.Empty(scaleResp.EvalID)
+
+	// TODO: check that scaling event was persisted
 }
 
 // TestJobs_ScaleStatus tests the /scale status endpoint for task group count

nomad/job_endpoint.go

@@ -894,7 +894,7 @@ func (j *Job) Scale(args *structs.JobScaleRequest, reply *structs.JobRegisterRes
 		return structs.NewErrRPCCoded(404, fmt.Sprintf("job %q not found", args.JobID))
 	}
 
-	index := job.ModifyIndex
+	jobModifyIndex := job.ModifyIndex
 	if args.Count != nil {
 		found := false
 		for _, tg := range job.TaskGroups {
@@ -917,22 +917,22 @@ func (j *Job) Scale(args *structs.JobScaleRequest, reply *structs.JobRegisterRes
 		}
 
 		// Commit this update via Raft
-		_, index, err = j.srv.raftApply(structs.JobRegisterRequestType, registerReq)
+		_, jobModifyIndex, err = j.srv.raftApply(structs.JobRegisterRequestType, registerReq)
 		if err != nil {
 			j.logger.Error("job register for scale failed", "error", err)
 			return err
 		}
-
 	}
 
 	// Populate the reply with job information
-	reply.JobModifyIndex = index
+	reply.JobModifyIndex = job.ModifyIndex
+	reply.Index = job.ModifyIndex
 
 	// FINISH:
 	// register the scaling event to the scaling_event table, once that exists
 
 	// If the job is periodic or parameterized, we don't create an eval.
-	if job != nil && (job.IsPeriodic() || job.IsParameterized()) {
+	if job != nil && (job.IsPeriodic() || job.IsParameterized()) || args.Count == nil {
 		return nil
 	}
 
@@ -946,7 +946,7 @@ func (j *Job) Scale(args *structs.JobScaleRequest, reply *structs.JobRegisterRes
 		Type:           structs.JobTypeService,
 		TriggeredBy:    structs.EvalTriggerScaling,
 		JobID:          args.JobID,
-		JobModifyIndex: index,
+		JobModifyIndex: jobModifyIndex,
 		Status:         structs.EvalStatusPending,
 		CreateTime:     now,
 		ModifyTime:     now,
@@ -966,7 +966,7 @@ func (j *Job) Scale(args *structs.JobScaleRequest, reply *structs.JobRegisterRes
 	// Populate the reply with eval information
 	reply.EvalID = eval.ID
 	reply.EvalCreateIndex = evalIndex
-	reply.Index = evalIndex
+	reply.Index = reply.EvalCreateIndex
 	return nil
 }